<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <style>
            div{
                margin-top: 100px;
                text-align: center;
            }
        </style>
    </head>
    <body>
           <div>
                <button id="start">开始</button>
                <button id="end">结束</button>
                <h1 id="txt">开始抽奖吧</h1>
            
           </div>
           
        <script>

            var tag=document.getElementById('txt');
            var start=document.getElementById('start');
            var end=document.getElementById('end');
            var timer;
            var list=['达咩达咩','咿咿呀呀','嘻嘻哈哈','噜噜啦啦','呼啦啦','李欣','李欣','李欣','李欣'];
            console.log(list[0]);
            console.log(list.length);
            start.onclick=function(){
                clearInterval(timer);
                timer=setInterval(function(){
                    var n=parseInt(Math.random()*list.length);
                    tag.innerHTML=list[n]
                },100)
            }
            end.onclick=function(){
                clearInterval(timer);
            }
        </script>
    </body>
</html>